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Abstract
The behaviour of ammonium perfluorooctanoate (APFO) and caesium perfluorooctanoate (CsPFO) in polar, organic solvents has been investigated. Only the APFO/ ethylene glycol system exhibits any mesophases (a lamellar phase). This phase occurs at high concentrations (mass fraction w >0.65) and at temperatures below 250 K, which are accessible only by supercooling below the solubility curve. The phase behaviour of APFO in mixtures of ethylene glycol and water has also been established. The nematic-to-isotropic transition in the APFO/ water system is found to be displaced to lower temperatures on incrementally replacing water with ethylene glycol. This is shown to arise from a contraction in the size of the disk-like micelles brought about by a lowering of the interfacial energy, an effect countered by lowering the temperature. Generally, the temperatures required fall well below the solubility curves preventing access to mesophases in perfluorocarbon surfactant/organic solvent systems.